Meet RoboSalmon, an underwater robot designed to spy on real fish (or so they say) by the Glasgow University.

A key feature of RoboSalmon is its propulsion system. Since the robot will use its fins and tail for movement, it will be able to move through the water in a way that is more natural for aquatic creatures. Propellers make an unnatural noise that disturbs fish; RoboSalmon's biomimetic characteristics should help it blend in